Turfgrass management compositions

ABSTRACT

The present invention relates to chemical compositions comprising imidazolinone compounds that are suitable for use in turfgrass management. The invention also provides methods for altering the growth and reducing mowing frequency, suppressing seed head formation and controlling undesirable vegetation in turfgrass.

This is a divisional of application Ser. No. 07/833,221 filed on Feb.10, 1992 (U.S. Pat. No. 5,340,791), which is a divisional of 07/411,444filed on Sep. 22, 1989 (U.S. Pat. No. 5,116,403) which is a continuationof Ser. No. 06/818,591 filed Jan. 15, 1986 (abandoned) which is a CIP of06/698,191 filed Feb. 4, 1985 (ABA).

BACKGROUND OF THE INVENTION

Maintenance of lawns, sport fields, playgrounds, parks, golf courses,roadsides and cemeteries represents a growing area of interest. Theannual investment in time, labor, chemical treatments, fertilization andequipment for the maintenance of turfgrasses was shown in 1965 to beover 4.2 billion dollars. Additionally, it was shown in 1965 that about50% of total annual lawn care expenditures was almost equally dividedbetween labor (23.5%) and equipment (26.5%).

Since a significant portion of the investment in turfgrass management isdevoted to labor costs, and the cost associated with purchasing,maintaining and operating maintenance equipment, it would be highlydesirable to be able to supplement turfgrass management practices withchemical treatments which reduce the maintenance requirements of thegrass. The development and use of chemical treatments which retard thegrowth of grass, and hence the frequency of mowing, reduce and inhibitheading, control undesirable weeds and are not injurious to the grassand do not alter its appearance could significantly reduce the overallmaintenance costs for turfgrass management.

Advances in the development of chemical herbicide treatments for thecontrol of weeds have resulted in a wide variety of chemicals which aresuitable for weed control in turf. Advances in the field of plant growthregulators have resulted in the discovery that certain of thesechemicals are suitable for use on turfgrasses For example, mefluidide,(Embark®)N-[2,4-dimethyl-5-[[(trifluoromethyl)sulfonyl]amino]phenyl]acetamide, aplant growth regulator produced by 3M Company, is registered for use asa growth and development retardant on turf and ornamental species. Morerecently, work in the area of turfgrass treatment has resulted in theevaluation of mixtures of chemicals in an attempt to enhance effects,improve safety margins, obtain several effects at the same time, reducerates of application or alter the effect obtained on one specificspecies.

Certain chemical combinations useful as turfgrass treatments werereported by K. J. Tautvydas in the Proceedings of Tenth Annual Meetingof the Plant Growth Regulator Society, 1983. This article disclosessynergistic growth retardation of Kentucky bluegrass and johnsongrasswith certain mixtures of mefluidide and chlorsulfuron,2-chloro-N-[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)aminocarbonyl]benzenesulfonamide,and a similar effect on bluegrass, johnsongrass and bermudagrass withcertain mixtures of mefluidide and methyl2-[[[[(4,6-dimethyl-2-pyrimidinyl)amino]carbonyl]amino]sulfonyl]benzoate.

While it is clear that a great deal of research and progress is beingmade in developing chemical compositions to aid in total turf managementprograms, it is also becoming clear that, due to variations in climaticconditions and differences in preferred grass varieties within thesedifferent growing regions, different treatments will probably berequired on a region-to-region and species-to-species basis.

SUMMARY OF THE INVENTION

It is an object of this invention to provide chemical compositionscontaining certain imidazolinone compounds of the formula (I) ##STR1##wherein X is N or CR₃ ; R is hydrogen; C₁ -C₁₂ alkyl optionallysubstituted with one of the following groups: C₁ -C₄ alkoxy, halogen,hydroxyl, C₃ -C₆ cycloalkyl, benzyloxy, furyl, phenyl, halophenyl, C₁-C₄ alkylphenyl, C₁ -C₄ alkoxyphenyl, nitrophenyl, carboxyl, C₁ -C₃alkoxycarbonyl, cyano, or tri(C₁ -C₃)alkylammonium;

C₃ -C₁₂ alkenyl optionally substituted with one of the following groups:C₁ -C₃ alkoxy, phenyl, halogen, or C₁ -C₃ alkoxycarbonyl or with two C₁-C₄ alkoxy groups or two halogen atoms;

C₃ -C₆ cycloalkyl optionally substituted with one or two C₁ -C₃ alkylgroups;

C₃ -C₁₀ alkynyl; or

a cation;

R₁ and R₂ are each hydrogen, halogen, C₁ -C₆ alkyl, C₁ -C₄ hydroxyalkyl,C₁ -C₆ alkoxy, C₁ -C₄ alkylthio, phenoxy, C₁ -C₄ haloalkyl, OCF₂ CHF₂,OCF₃, OCHF₂, nitro, cyano, C₁ -C₄ alkylsulfonyl, NR₄ R₅, C₃ -C₈ straightor branched alkenyloxy optionally substituted with one to threehalogens, C₃ -C₈ straight or branched alkynyloxy optionally substitutedwith one to three halogens, or phenyl optionally substituted with one C₁-C₄ alkyl, C₁ -C₄ alkoxy or halogen;

R₃ is hydrogen, halogen, C₁ -C₄ alkyl, C₁ -C₄ alkylthio, C₁ -C₄ alkoxy,CF₃, NO₂, OCF₃, OCHF₂, or OCF₂ CHF₂ ;

R₄ is hydrogen or C₁ -C₄ alkyl;

R₅ is C₁ -C₄ alkyl;

and, when taken together, R₁ and R₂, in the case of X=CR₃, may form aring in which R₁ R₂ is represented by

(1) the structure: --(CH₂)_(n) --, where n is an integer of 2, 3 or 4;or

(2) by the structure: ##STR2## where L, M, R₆ and R₇ each representhydrogen, halogen, C₁ -C₄ alkyl or C₁ -C₃ alkoxy;

and, in the case of X=N, R₁ and R₂

(1) may form a ring in which R₁ R₂ is represented by the structure--(CH₂)_(n) --, where n is an integer of 3 or 4; or

(2) when taken together with the carbons to which they are attached mayform a 5-membered ring containing one O or S; or

(3) may form a ring represented by the structure: ##STR3## where L, M,R₆ and R₇ each represent hydrogen, halogen, C₁ -C₄ alkyl, C₁ -C₄ alkoxy,C₁ -C₄ alkylthio, C₁ -C₄ alkylsulfonyl, C₁ -C₄ haloalkyl, NO₂, CN,phenyl, phenoxy, amino, C₁ -C₄ alkylamino, diloweralkylamino,chlorophenyl, methylphenyl, phenoxy substituted with one C₁, CF₃, NO₂,or CH₃ group, OCF₂ CHF₂, OCF₃, OCHF₂, C₃ -C₈ straight or branchedalkenyloxy optionally substituted with one to three halogens, or C₃ -C₈straight or branched alkynyloxy optionally substituted with one to threehalogens; and the N-oxides thereof when X=N, provided that R cannot bealkenyl or alkynyl and R₁ and R₂ cannot be NR₄ R₅ or alkylthio, and theoptical isomers thereof and mixtures of regio isomers thereof,

alone and in combination with2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)nicotinic acid or saltsthereof, maleic hydrazide,N-[2,4-dimethyl-5-[[(trifluoromethyl)sulfonyl]amino]phenyl]acetamide,2-chloro-N-[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)aminocarbonyl]benzenesulfonamide or methyl2-[[[[(4,6-dimethyl-2-pyrimidinyl)amino]carbonyl]amino]sulfonyl]benzoateand mixtures thereof, which provide compositions that reduce growth in avariety of grass species, without being injurious, inhibit seed heading,and control certain weeds, and further that the desired effect or groupof effects for a given variety of grass under specific growingconditions may be obtained by altering the combination and rate of eachcomponent.

The imidazolinone compounds suitable for use in turf described in U.S.Pat. No. 4,188,487, pending applications for U.S. letters patent Ser.No. 382,041 (U.S. Pat. No. 4,638,068), U.S. Ser. No. 616,747(abandoned), U.S. Ser. No. 631,283 (U.S. Pat. No. 4,554,013), U.S. Ser.No. 611,191 (abandoned) and pending application for U.S. letters patent,Ser. No. 635,787 (abandoned) as herbicides and plant growth regulatorsfor increasing crop yields. Surprisingly, it has been found thatcompounds represented by Formula (I) are efficacious for retarding thegrowth of turf and suppressing seed heads. Additionally, it has beenfound that the longevity of the effect and the extent of the effect maybe increased significantly by applying formula (I) compounds incombination with one or more of2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)nicotinic acid or saltsthereof, maleic hydrazide,N-[2,4-dimethyl-5-[[(trifluoromethyl)sulfonyl]amino]phenyl]acetamide,2-chloro-N-[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)aminocarbonyl]benzenesulfonamideand methyl2-[[[[(4,6-dimethyl-2-pyrimidinyl)amino]carbonyl]amino]sulfonyl]benzoate.Further, it has been found that by altering the rates of each of thecomponents, the desirable effects of growth retardation, head inhibitionand control of certain weeds may be obtained in a variety of grassspecies without being injurious to the grass. Preferred compoundssuitable for use in turfgrass management compositions of the inventionare illustrated in Table I below.

                  TABLE I                                                         ______________________________________                                        Component                                                                     ______________________________________                                                 ##STR4##                                                             (a)             X      R    R.sub.1     R.sub.2                                               N      H    H           OCH.sub.3                             (b)             N      H    CHCHCHCH                                           (c)             CH     CH .sub.3                                                                          CH .sub.3   H                                                    +                                                                             CH     CH.sub.3                                                                           H           CH.sub.3                              (d)             N      H    OCH.sub.2 CHCH.sub.2                                                                      H                                     (e)             N      H    CH.sub.2 CH.sub.2 O                               (f)             N      C.sub.2 H.sub.5                                                                    OCH.sub.3   H                                     (g)             N      H                                                                                   ##STR5##                                         (h)             N      H    C.sub.2 H.sub.5                                                                           H                                     (i)             N      H                                                      phenyl    H                                                                   (j)             N      H                                                                                   ##STR6##                                         (k)             N      CH.sub.3                                                                           H           OCH.sub.3                             ______________________________________                                        2               2-(4-isopropyl-4-methyl-5-oxo-2-imidazo-                                      lin-2-yl)nicotinic acid                                       3               maleic hydrazide                                              4                N-[.sup.1 2,4-dimethyl-5-[[(trifluoromethyl)-                                sulfonyl]amino]phenyl]acetamide                               5               chlorsulfuron, 2-chloro-N-[(4-methoxy-6-                                      methyl-1,3,5-triazin-2-yl)aminocarbonyl]-                                     benzenesulfonamide                                            6               methyl 2-[[[[(4,6-dimethyl-2-pyrimidinyl)-                                    amino]carbonyl]amino]sulfonyl]benzoate                        ______________________________________                                    

As indicated above, the composition of the invention may be altered toobtain different effects or the same set of effects on a different grassspecies without injuring the grass. The preferred ranges of rates foreach of the components are illustrated in Table II below.

                  TABLE II                                                        ______________________________________                                        Preferred rate ranges for turf management                                     compositions of the invention                                                 Composition   Rate grams/hectare                                              ______________________________________                                        1             5 to 500                                                        2             0.1 to 200                                                      1 + 2         5 to 250 + 0.25 to 25                                           1 + 3         5 to 250 + 20 to 5000                                           1 + 4         5 to 250 + 20 to 500                                            1 + 5         5 to 250 + 0.25 to 20                                           1 + 6         5 to 250 + 0.25 to 20                                           1 + 2 + 4     1 to 250 + 0.25 to 25 + 20 to 500                               1 + 2 + 5     1 to 250 + 0.25 to 25 + 0.25 to 20                              1 + 2 + 6     1 to 250 + 0.25 to 25 + 0.25 to 20                              ______________________________________                                    

As discussed above, by adjusting the rates of each component thecompositions may be used on a variety of species as indicated in TableIII below.

                                      TABLE III                                   __________________________________________________________________________    Adjusting Composition for different grass species                             Composition                                                                          Bermudagrass                                                                           Bluegrass                                                                              Fescue      Rye                                      __________________________________________________________________________    1      5.0 to                                                                            500.0*                                                                             5.0 to                                                                            500.0                                                                              5.0 to 250.0                                                                              5.0 to                                                                            250.0                                2      5.0 to                                                                            200.0                                                                              0.1 to                                                                            20.0 0.1 to 10.0 0.1 to                                                                            10.0                                 1 + 2  5.0 to                                                                            250.0 +                                                                            5.0 to                                                                            250.0 +                                                                            5.0 to 150.0 +                                                                            5.0 to                                                                            150.0 +                                     0.25 to                                                                           25.0 0.25 to                                                                           25.0 0.5 to 10.0 0.5 to                                                                            10.0                                 1 + 3  5.0 to                                                                            250.0 +                                                                            5.0 to                                                                            250.0 +                                                                            5.0 to 150.0 +                                                                            5.0 to                                                                            150.0 to                                    20.0 to                                                                           5000.0                                                                             20.0 to                                                                           5000.0                                                                             20.0 to                                                                              2500.0                                                                             20.0 to                                                                           2500.0                               1 + 4  50.0 to                                                                           250.0 +                                                                            5.0 to                                                                            250.0 +                                                                            5.0 to 150.0 +                                                                            5.0 to                                                                            150.0 +                                     0.25 to                                                                           10.0 0.25 to                                                                           10.0 0.25 to                                                                              5.0  0.25 to                                                                           5.0                                  1 + 5  5.0 to                                                                            250.0 +                                                                            5.0 to                                                                            250.0 +                                                                            5.0 to 150.0 +                                                                            5.0 to                                                                            150.0 +                                     0.25 to                                                                           10.0 0.25 to                                                                           10.0 0.25 to                                                                              5.0  0.25 to                                                                           5.0                                  1 + 6  5.0 to                                                                            250.0 +                                                                            5.0 to                                                                            250.0 +                                                                            5.0 to 150.0 +                                                                            5.0 to                                                                            150.0 +                                     0.25 to                                                                           10.0 0.25 to                                                                           10.0 0.25 to                                                                              5.0  0.25 to                                                                           5.0                                  1 + 2 + 4                                                                            1 to                                                                              250 +                                                                              1 to                                                                              250 +                                                                              1 to   250 +                                                                              1 to                                                                              250 +                                       0.25 to                                                                           25 + 0.25 to                                                                           25 + 0.25 to                                                                              10 + 0.25 to                                                                           10 +                                        20 to                                                                             500  20 to                                                                             500  20 to  500  20 to                                                                             250                                  1 + 2 + 5                                                                            1 to                                                                              250 +                                                                              1 to                                                                              250 +                                                                              1 to   250+ 1 to                                                                              250 +                                       0.25 to                                                                           25 + 0.25 to                                                                           25 + 0.25 to                                                                              25 + 0.25 to                                                                           25 +                                        0.25 to                                                                           10   0.25 to                                                                           10   0.25 to                                                                              5    0.25 to                                                                           5                                    1 + 2 + 6                                                                            1 to                                                                              250 +                                                                              1 to                                                                              250 +                                                                              1 to   250 +                                                                              1 to                                                                              250 +                                       0.25 to                                                                           25 + 0.25 to                                                                           25 + 0.25 to                                                                              25 + 0.25 to                                                                           25 +                                        0.25 to                                                                           10   0.25 to                                                                           10   25 + 0.25 to                                                                         5    0.25 to                                                                           5                                    __________________________________________________________________________     *Rate in grams/hectare                                                   

The compositions of the invention may conveniently be applied bypost-emergence treatment of the grass. They may be applied as a mixtureof all the ingredients or as sequential treatments. Since the formula(I) compounds wherein R is hydrogen are acids, as is2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)nicotinic acid and thesecompounds may be applied as salts of the acid wherein R is asalt-forming cation, the compositions may be applied as aqueoussolutions and suspensions containing non-ionic surfactants, and wettingagents which may be prepared by introducing the components directly towater or by adding formulations such as concentrates, suspensions,emulsions, wettable powders, dispersible granules and the like to waterprior to application. Additionally granular compositions containing someof the compositions of the invention may be applied to the turf followedby additional post-emergence treatments as required. The invention isfurther illustrated by the following non-limiting examples.

EXAMPLE 1

Evaluation of compositions of the invention for retarding growth

Seeds of the grass variety to be evaluated are tumbled for three minuteswith soil at a rate of 7 ounces of seed per 100 lbs of greenhouse soil,comprising a mixture by weight of sand (32%), silt (48%), and clay(20%). A layer of this seed mixture one-half inch thick is placed in afour inch diameter pot containing greenhouse soil and the plants areallowed to germinate and grow for six to eight weeks prior to treatment.The plants are clipped to a height of one-half inch and are sprayed with100 mL of an aqueous solution containing 0.25% by volume of a nonionicsurfactant mixture alkylarylpolyoxyethyleneglycols, free fatty acids and2-propanol, and the formula I (a)-(k) compounds and compounds 2, 3, 4,and 5 both alone and in combinations at various spray rates. Eachtreatment is applied to three pots and the pot randomly placed in agreenhouse where the plants are cared for employing standard greenhouseprocedures. Three weeks after treatment the plants are clipped to aheight of one-half inch and the clippings are dried in an oven for 48hours at 90° C. and the dry weight of clippings for each treatment isrecorded. Examination of Tables IV and V below which is a summary ofresults obtained on tall fescue and bermudagrass, respectively, clearlydemonstrates the effectiveness of the formula I (a)-(k) compounds aloneand additionally demonstrates the improved effectiveness of theseformula I (a)-(k) compounds in combination with compounds 2, 3, 4 and 5for retarding the growth of turfgrasses as measured by dry clippingweight.

                  TABLE IV                                                        ______________________________________                                        Greenhouse evaluation of compositions of                                      the invention on tall fescue (Festuca arundinaceae)                                      Rate(s)      % Decrease in                                         Treatments g or lb/A    dry wt of clipping                                    ______________________________________                                        1(h)       20.0 g       37                                                    1(h)       40.0 g       51                                                    2           1.0 g        2                                                    2           2.0 g        3                                                    1(j)       20.0 g       29                                                    1(j)       40.0 g       32                                                    1(j)       60.0 g       25                                                    1(h) + 2   20.0 g + 1.0 g                                                                             52                                                    1(h) + 2   20.0 g + 2.0 g                                                                             52                                                    1(h) + 2   40.0 g + 1.0 g                                                                             37                                                    1(h) + 2   40.0 g + 2.0 g                                                                             76                                                    4           0.125 lb     6                                                    4           0.375 lb    59                                                    1(h) + 4   20.0 g + 0.125 lb                                                                          80                                                    1(j) + 4   40.0 g + 0.125 lb                                                                          82                                                    1(j) + 4   20.0 g + 0.125 lb                                                                          60                                                    1(j) + 4   40.0 g + 0.125 lb                                                                          46                                                    1(j) + 4   60.0 g + 0.125 lb                                                                          64                                                    3           1.5 lb       2                                                    3           3.0 lb       7                                                    1(h) + 3   20.0 g + 1.5 lb                                                                            45                                                    1(h) + 3   40.0 g + 1.5 lb                                                                            66                                                    1(j) + 3   20.0 g + 1.5 lb                                                                            70                                                    1(j) + 3   20.0 g + 1.5 lb                                                                            70                                                    1(j) + 3   40.0 g + 1.5 lb                                                                            49                                                    1(j) + 3   60.0 g + 1.5 lb                                                                            46                                                    ______________________________________                                    

                  TABLE V                                                         ______________________________________                                        Greenhouse evaluation of compositions of the invention                        on burmudagrass (Cynodon sp)                                                               Rates      % Decrease in                                         Treatments   (grams/Acre)                                                                             dry wt of clippings                                   ______________________________________                                        1(h)          5.0       15.3                                                  1(h)          10.0      14.7                                                  1(h)          15.0      12.7                                                  1(h)          20.0      12.7                                                  1(h)          40.0      57.3                                                  1(h)         100.0      71.3                                                  2             2.00      24.7      Increase                                    2             4.00      8.0       Increase                                    2             6.00      59.3                                                  2             8.00      82.0                                                  1(h) + 2      5.0 + 2.0 19.3                                                  1(h) + 2      5.0 + 4.0 44.7                                                  1(h) + 2      5.0 + 8.0 82.0                                                  1(h) + 2      10.0 + 0.5                                                                              34.0                                                  1(h) + 2      10.0 + 1.0                                                                              5.3                                                   1(h) + 2      10.0 + 2.0                                                                              38.7                                                  1(h) + 2      10.0 + 4.0                                                                              52.0                                                  1(h) + 2      10.0 + 6.0                                                                              86.0                                                  1(h) + 2      10.0 + 8.0                                                                              86.7                                                  1(h) + 2      15.0 + 0.25                                                                             38.7                                                  1(h) + 2      15.0 + 0.5                                                                              18.7                                                  1(h) + 2      15.0 + 1.0                                                                              2.0       Increase                                    1(h) + 2      15.0 + 2.0                                                                              8.0       Increase                                    1(h) + 2      15.0 + 4.0                                                                              10.7                                                  1(h) + 2      15.0 + 6.0                                                                              83.3                                                  1(h) + 2      15.0 + 8.0                                                                              78.0                                                  1(h) + 2      20.0 + 0.25                                                                             48.7                                                  1(h) + 2      20.0 + 0.5                                                                              16.7                                                  1(h) + 2      20.0 + 1.0                                                                              18.0                                                  1(h) + 2      20.0 + 2.0                                                                              54.0                                                  1(h) + 2      20.0 + 4.0                                                                              45.3                                                  1(h) + 2      20.0 + 6.0                                                                              66.7                                                  1(h) + 2      25.0 + 0.25                                                                             7.3                                                   1(h) + 2      25.0 + 0.50                                                                             27.3                                                  1(h) + 2      25.0 + 1.0                                                                              36.7                                                  1(h) + 2      25.0 + 2.0                                                                              75.3                                                  1(h) + 2      25.0 + 4.0                                                                              76.0                                                  1(h) + 2      30.0 + 6.0                                                                              88.0                                                  1(h) + 2      30.0 + 0.25                                                                             36.7                                                  1(h) + 2      30.0 + 0.50                                                                             20.0                                                  1(h) + 2      30.0 + 1.0                                                                              42.7                                                  1(h) + 2      30.0 + 2.0                                                                              78.0                                                  1(h) + 2      30.0 + 4.0                                                                              64.7                                                  1(h) + 2      30.0 + 0.25                                                                             16.0                                                  1(h) + 2      35.0 + 0.50                                                                             44.0                                                  1(h) + 2      35.0 + 1.0                                                                              31.3                                                  1(h) + 2      35.0 + 2.0                                                                              58.7                                                  1(h) + 2      40.0 + 0.25                                                                             48.0                                                  1(h) + 2      40.0 + 0.50                                                                             32.7                                                  1(h) + 2      40.0 + 1.0                                                                              42.0                                                  1(h) + 2      40.0 + 2.0                                                                              68.0                                                  4             50.0      5.3                                                   4            100.0      5.3       Increase                                    4            500.0      48.0                                                  1(h) + 4      10.0 + 50.0                                                                             35.3                                                  1(h) + 4      10.0 + 100.0                                                                            27.3                                                  1(h) + 4      10.0 + 500.0                                                                            47.3                                                  1(h) + 4      15.0 + 50.0                                                                             12.0                                                  1(h) + 4      15.0 + 100.0                                                                            4.0                                                   1(h) + 4      15.0 + 500.0                                                                            17.3                                                  1(h) + 4      20.0 + 50.0                                                                             29.3                                                  1(h) + 4      20.0 + 100.0                                                                            34.0                                                  1(h) + 4      20.0 + 500.0                                                                            50.0                                                  1(h) + 4      25.0 + 50.0                                                                             54.0                                                  1(h) + 4      25.0 + 100.0                                                                            63.3                                                  1(h) + 4      25.0 + 500.0                                                                            12.0                                                  2 + 4         0.5 + 50.0                                                                              9.3       Increase                                    2 + 4         0.5 + 100.0                                                                             18.0      Increase                                    2 + 4         0.5 + 500.0                                                                             36.7                                                  2 + 4         1.0 + 50.0                                                                              33.3                                                  2 + 4         1.0 + 100.0                                                                             42.0                                                  2 + 4         1.0 + 500.0                                                                             48.0                                                  2 + 4         2.0 + 50.0                                                                              26.7                                                  2 + 4         2.0 + 100.0                                                                             48.0                                                  2 + 4         2.0 + 500.0                                                                             75.3                                                  2 + 4         4.0 + 50.0                                                                              37.3                                                  2 + 4         4.0 + 100.0                                                                             20.7                                                  2 + 4         4.0 + 500.0                                                                             33.3                                                  ______________________________________                                    

EXAMPLE 2

Evaluation of compositions of the invention on a mix stand of grasseswhich include tall rescue (Festuca arundinaecae); Kentucky bluegrass(Poa pratensis), annual ryegrass (Lolium multiforum) and perennialryegrass (Lolium perenne)

A six foot by twenty foot plot containing a mixed stand of grasses whichinclude tall rescue (Festuca arundinaecae); Kentucky bluegrass (Poapratensis), annual ryegrass (Lolium multiforum) and perennial ryegrass(Lolium perenne) is mowed at a height of one and one-half inches.Twenty-four hours after mowing the plot is sprayed with an aqueoussolution containing 0.25% by volume of a nonionic surfactant mixture ofalkylarylpolyoxyethyleneglycols, free fatty acids, and 2-propanol andformula I (a)-(k) compounds and compounds 2, 3, 4 and 5 alone and incombinations at a variety of concentrations. Sufficient aqueous solutionis applied to provide the equivalent of 25 gal/acre of spray. Eachtreatment is applied to three plots which are situated randomly withinthe test area and the results for each treatment are obtained byaveraging the three replicates. The height of each treatment plot ismeasured at three weeks and five weeks after treatment to determine theeffectiveness of The treatment in retarding growth. Examination of TableVI below which is a summary of the results obtained on the mixed standof grasses demonstrates the effectiveness of The formula I (a)-(k)compounds alone and additionally demonstrates the improved effectivenessof these formula I (a)-(k) compounds in combination with compounds 2, 3,4 and 5 for retarding the growth of turfgrasses.

                  TABLE VI                                                        ______________________________________                                        Evaluation of compositions of the invention on a                              mix stand of grasses which include Tall Fescue                                (Festuca arundinaecae), Kentucky Bluegrass                                    (Poa pratensis), Annual Ryegrass (Lolium multiforum)                          and Perennial Ryegrass (Lolium perenne)                                                           % Decrease                                                                    in height                                                            Rate(s)        22-25   36-38                                       Treatments g or lb/A      DAT*    DAT*                                        ______________________________________                                        1(h)       25.0 g         16      --                                          1(h)       50.0 g         24      --                                          1(h)       75.0 g         10      --                                          1(b)        1.0 g         14      --                                          1(b)        2.0 g         30      19                                          1(b)        2.5 g         --      --                                          1(b)        5.0 g         --      --                                          1(d)       25.0 g         10      --                                          1(d)       50.0 g         14      --                                          1(d)       75.0 g         23      --                                          1(a)       20.0 g         38      37                                          1(a)       40.0 g         42      40                                          1(a)       60.0 g         37      34                                          3           5.0 lb        14      --                                          5           3.5 g          8      --                                          5           7.0 g          4      --                                          4           0.5 lb        23      8                                           1(h) + 1(b)                                                                              25.0 g + 2.5 g --      --                                          1(h) + 1(b)                                                                              25.0 g + 5.0 g 15      --                                          1(h) + 2   25.0 g + 1.0 g 28      --                                          1(h) + 2   25.0 g + 2.0 g 29      --                                          1(h) + 2   50.0 g + 1.0 g --      10                                          1(h) + 2   50.0 g + 2.0 g 26      12                                          1(d) + 2   25.0 g + 1.0 g 23      --                                          1(d) + 2   25.0 g + 2.0 g 11      --                                          1(h) + 3   25.0 g + 1.5 lb                                                                              16      13                                          1(h) + 3   50.0 g + 1.5 lb                                                                              29      12                                          1(h) + 4   25.0 g + 0.125 lb                                                                            42      16                                          1(h) + 4   50.0 g + 0.125 lb                                                                            38      27                                          1(h) + 5   20.0 g + 3.5 g 16      --                                          1(d) + 4   25.0 g + 0.125 lb                                                                            37      13                                          1(d) + 5   25.0 g + 3.5 g 19      13                                          1(d) + 3   25.0 g + 1.5 lb                                                                              31      13                                          1(d) + 3   50.0 g + 1.5 lb                                                                              29      14                                          1(k)       20.0 g         27      --                                          1(k)       40.0           29      11                                          1(k)       60.0 g         24      31                                          1(k)       80.0 g         37      41                                          1(d)       20.0 g         22      --                                          1(d)       40.0 g         24      --                                          1(d)       60.0 g         19      --                                          1(d)       80.0 g         35      23                                          2           1.0 g         --      --                                          2           2.0 g         --      7.2                                         1(k) + 2   20.0 g + 1.0 g 21      16                                          1(k) + 2   20.0 g + 2.0 g 28      25                                          1(k) + 2   40.0 g + 1.0 g 22      34                                          1(k) + 2   40.0 g + 2.0 g 32      30                                          1(d) + 2   20.0 g + 1.0 g 16      --                                          1(d) + 2   20.0 g + 2.0 g 19      13                                          1(d) + 2   40.0 g + 1.0 g 19      --                                          1(d) + 2   40.0 g + 2.0 g 26      29                                          4           0.125 lb      26      29                                          4           0.375 lb      15      19                                          4 + 2       0.125 lb + 1 g                                                                              34      29                                          4 + 2       0.125 lb + 2 g                                                                              38      25                                          4 + 1(k)    0.125 lb + 20 g                                                                             31      23                                          4 + 1(d)    0.125 lb + 20 g                                                                             29      13.5                                        5           2.0 g         --      --                                          5           7.0 g         15      --                                          5 + 2       2.0 g + 1.0 g 21      4                                           5 + 4 + 2   2.0 g + 0.125 g +                                                                           28      5.8                                                     1.0 g                                                             5 + 4 + 1(d)                                                                              2.0 g + 0.125 g +                                                                           27      --                                                     20.0 g                                                             5 + 4 + 1(k)                                                                              2.0 g + 0.125 g +                                                                           44      10                                                     20.0 g                                                             ______________________________________                                         *DAT = Days after treatment                                              

EXAMPLE 3

Evaluation of2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)-5-methyl-nicotinic acidfor retarding growth of turfgrasses

An evaluation of another composition of the invention is conducted usingthe procedure of Example 1 above and Bermudagrass (Cynodon doctylon) asthe turfgrass species.

The test composition,2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-yl)-5-methyl-nicotinic acid,is applied to said turfgrass at rates of from 25 to 200 grams perhectare. Test compound is applied in the form of an aqueous solution asdescribed in Example 1 and treated plants were held in the greenhousefor 60 days after treatment and then harvested.

Data obtained are reported in Table VII below.

                  TABLE VII                                                       ______________________________________                                        Rate  Phytotoxicity                                                                              Clipping*     Clipping*                                    (g/ha)                                                                              Rating**     Fresh Weight (g)                                                                            Dry Weight (g)                               ______________________________________                                         0    0            369           97                                            25   0            231 (37.4%)   59 (39.1%)                                    50   0            209 (43.3%)   54 (44.3%)                                   100   1            163 (55.8%)   41 (57.7%)                                   150   3            114 (69.1%)   30 (69.0%)                                   200   5             68 (81.5%)   23 (76.2%)                                   ______________________________________                                         *% Reduction over checks is shown in parenthesis.                             **Phytotoxicity Rating ranges from 0 meaning no injury to 10 meaning          complete kill.                                                           

What is claimed is:
 1. A composition for retarding growth and suppressing seed heading in turfgrasses, comprising a synergistic effective amount of at least one compound having the structure: ##STR7## wherein X is N or CH; R is H, C₁ -C₄ alkyl, or a cation; R₁ and R₂ are each H, C₁ -C₄ alkyl, C₁ -C₄ alkyloxy, C₃ -C₆ alkenyloxy, or R₁ and R₂ taken together with the carbons to which they are attached may form a 6 membered ring; and the optical isomer thereof, in combination with N-[2,4-dimethyl-5[[(trifluoromethyl)-sulfonyl]amino]phenyl]acetamide.
 2. A composition according to claim 1, comprising a mixture of 2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl) 3-quinolinecarboxylic acid and N-[2,4dimethyl-5-[[(trifluoromethyl)sulfonyl]amino]phenyl]acetamide.
 3. A composition according to claim 1, comprising a mixture of 5-ethyl-2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)nicotinic acid and N-[2,4-dimethyl-5-[[(trifluoromethyl)sulfonyl]amino]phenyl]acetamide.
 4. A composition according to claim 1, comprising a mixture of methyl 6-(5-isopropyl-5-methyl-4-oxo-2-imidazolin-2-yl) m-toluate and methyl 2-(5-isopropyl-5-methyl-4-oxo-2-imidazolin-2-yl) p-toluate and N-[2,4-dimethyl-5-[[(trifluoromethyl)sulfonyl]amino]phenyl]acetamide.
 5. A composition according to claim 1, comprising a mixture of methyl 2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)-6-methoxy nicotinate and N-[2,4-dimethyl-5-[[(trifluoromethyl)sulfonyl]amino]phenyl]acetamide.
 6. A composition according to claim 1, comprising a mixture of 5-(allyloxy)-2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)nicotinic acid and N-[2,4-dimethyl-5-[[(trifluoromethyl)sulfonyl]amino]phenyl]acetamide.
 7. A composition according to claim 1, comprising 2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)nicotinic acid or salts thereof and N-[2,4-dimethyl-5-[[(trifluoromethyl)sulfonyl]amino]phenyl]acetamide.
 8. A method for retarding growth and suppressing seedheading in turfgrasses, which comprises applying to the foliage or soil surrounding the turfgrasses, a sufficient quantity of a composition having a synergistic effective amount of at least one compound comprising the structure: ##STR8## wherein X is N or CH; R is H, C₁ -C₄ alkyl, or a cation; R₁ and R₂ are each H, C₁ -C₄ alkyl, C₁ -C₄ alkyloxy, C₃ -C₆ alkenyloxy, or R₁ and R₂ taken together with the carbons to which they are attached may form a 6 membered ring: and the optical isomer thereof, in combination with N-[2,4-dimethyl-5[[(trifluoromethyl)-sulfonyl]amino]phenyl]acetamide.
 9. A method according to claim 8, comprising applying to turfgrasses a mixture of 2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl) 3-quinolinecarboxylic acid and N-[2,4-dimethyl-5-[[(trifluoromethyl)sulfonyl]amino]phenyl]acetamide.
 10. A method according to claim 8, comprising applying to turfgrasses a mixture of 5-ethyl-2-(4- isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl )nicotinic acid and N-[2,4-dimethyl-5-[[(trifluoromethyl)sulfonyl]amino]phenyl]acetamide.
 11. A method according to claim 8, comprising applying to turfgrasses a mixture of methyl 6-(5-isopropyl-5-methyl-4-oxo-2-imidazolin-2-yl) m-toluate and methyl 2-(5-isopropyl-5-methyl-4-oxo-2-imidazolin-2-yl) p-toluate and N-[2,4-dimethyl-5[[(trifluoromethyl)sulfonyl]amino]phenyl]acetamide.
 12. A method according to claim 8, comprising applying to turfgrasses a mixture of methyl 2- (4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)-6-methoxy nicotinate and N-[2,4-dimethyl-5-[[(trifluoromethyl)sulfonyl]amino]phenyl]acetamide.
 13. A method according to claim 8, comprising applying to turfgrasses a mixture of 5-(allyl-oxy)-2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)nicotinic acid and N-[2,4-dimethyl-5-[[(trifluoromethyl)sulfonyl]amino]phenyl]acetamide.
 14. A method according to claim 8, comprising applying to turfgrasses a mixture of 2-(4-isopropyl-4-methyl-5-oxo-2- imidazol in-2-yl )nicotinic acid or salt thereof and N-[2,4-dimethyl-5-[[(trifluoromethyl)sulfonyl]amino]phenyl]acetamide.
 15. A method according to claim 8, wherein the formula I compound is 2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)-5-methyl-nicotinic acid or salt thereof.
 16. A method according to claim 8, wherein the formula I compound is 2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)-5-methyl-nicotinic acid or salt thereof and is applied to the foliage or soil surrounding said turfgrasses at the rate of from 5.0 to 500.0 grams per hectare alone, or in combination with from 0.1 to 200.0 grams per hectare of another formula I imidazolinone compound or 20.0 to 500.0 grams per hectare of maleic hydrazide; and 20.0 to 500.0 grams per hectare of N-[2,4-dimethyl-5-[[(trifluoromethyl)sulfonyl]amino]phenyl]acetamide. 